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Most Versatile Focal Length for a Telescope?
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- čas přidán 25. 07. 2024
- Astrophotography food fight! What do you think is the most versatile focal length for a telescope and astrophotography? Which telescopes are the most enjoyable to use? I review my impressions of telescope focal length after 1 year with my three telescopes (William Optics Redcat 51, Explore Scientific ED102, and the Celestron C9.25 SCT). We're interested in cost, ease of use, and target selection.
Hi James,
I just came across your video,
Ooh my word, I throughly enjoyed it,
I have watched hundreds of videos and yours have answered so many questions,
I know it’s been 3 years, but it’s still making A impact
I’m in Melbourne Australia,
Thanks James
Fantastic review. Thanks very much for all your effort in putting this together James!
Thanks, Andrew! For me, it goes in the category of "wish I knew then, what I know now"
One of if not the best video I have seen yet explaining the differences, targets, pro, and cons. Thank you. Be safe!
Thanks, Ron! There's a lot of stuff up there, we need the right tool for the job. Clear skies!
Great presentation. This was the most informative yet succinct description and comparison of focal length/target selection I’ve seen. Nicely reviewed and expertly summed up at the end. Thanks, James.
Thanks for watching, Robert! And thanks for the kind words!
Very comprehensive video James!! Thank you for your work.
Glad you enjoyed it, Antonio!
Awesome and informative video, thanks for putting in the time and effort to make this video. Your videos are well made, easy to understand and you voice is extremely clear and at the correct volume :) Thank you!
Thanks for the kind words! Glad you found it useful.
Great video. Stumbled across your channel recently and loving the quality and detail of your content. Thanks for great info, looking forward to following your channel.
Thanks for watching, Chris!
Right, huge learning curve with challenges around every corner. So many options and variations keep this hobby interesting. It does require patience, patience, and more patience which I am finding out every session. And then the rewards are breathtaking with success. Excellent video!
Thanks for watching! Yep, it's nice to score a success every now and then amid all of the frustrating events that occur along the way.
I really appreciate the way you organize information in your videos. It's very concise and apt. Well done Sir!
Thanks for watching, Chaithu!
Thank you! You answered questions I didn't even know I had.😀
HaHa. Best kind of answers. Worse kind of questions. Thanks for watching, Bill!
Always great videos. Clear and quantitative. I always learn something from you.
Thanks for watching, John!
Without a doubt one of the best and informative astrophotography videos to date that I have viewed and I have viewed hundreds. Your video provides a wonderful (sane) baseline of information for one who is interested in astrophotography. Still eating around the edges for now but when I bite your video has brought a little sanity for me in making an informed choice. Following you. Keep up your great work.
Thanks for watching. David! Glad you found it useful. Clear Skies!
such a wonderfully comprehensive video! stellar pics. thanks!
Thanks for watching, Nikhil!
I loved this video. Put so much of our hobby into perspective. More tools in our armamentarium just serves to increase our understanding of the expanse of our universe. Certainly frustration is directly proportional to focal length. The planetarium quality ending was just phenomenal. Keep up the great work.
Thanks, Louis! I know what you mean. I spent so much of my first years with only the SCT. The wide field refractors have really been a pleasant eye-opening surprise. Just imagine how awesome our nights would be if we could see these huge nebula in SHO colors with the naked eye. Oh well. They'll just have to be the astrophotographer's secret I guess. Thanks for watching!
Excellent review and breakdown of pros and cons for both. Exactly what I was looking for. Thx!
Glad it was helpful, Brent!
Great summary, thanks for taking the time to do this
Thanks for watching, Brian!
This fella is answering all my questions haha shame I already own 6 imaging scopes, this is a must for anyone new to AP could save so much money and time
You mean there IS a way to save money in AP? Who knew!? Thanks for watching and subscribing, Clint!
Thank you so much for explaining all needed to know about this task. I must have a lot of patience. Excellent video to understand. Thank you very much again.
Patience indeed! Thanks for watching, Donald!
Great video! Getting into ASP this year and can't wait. First though I'm gonna spend the summer getting familiar with the sky with a 10" dubs that's arriving in a couple days and I'm so excited! This year is gonna be awesome! :D
Welcome to the journey! Clear skies!
Thank you for the very informative video. I’m still in the information gathering part of obtaining a new telescope. I’ve been going back and forth on ALL the different types. Your video spelled out the differences. Thank you again.
Good luck, Ron! You can’t go wrong. Chances are that which ever one you start out with, you’ll be getting one of the others before too long. Clear skies!
Nice video James! I remember when I was getting into this hobby everyone told me to stay away from SCTs, but I went that route anyway. Was it difficult at times, definitely. But in the end I'm so glad I went for it because everything else seems simple now by comparison!
You speak TRUTH, my friend. People might be in for a ruder awakening if they start out with a hassle-free small reflector and then get hit in the face with the challenges presented by an SCT. Thanks for watching, Kyle!
I went for a Newtonian, and honestly i don't regret it. Because the refractors I've been recommended are now my guide scopes.
This is exactly the info i was looking for. Thank you!
Great! I hope it’s useful for you. Thanks for watching!
Thank you James, as a beginner I appreciate the logical flow and clarity of your reasoning. After a lot of reading I had almost understood the tradeoffs to be taken, but you lay them down so simple and clean that they now look obvious. I'm your fan now!
Thanks for watching! Glad you found it helpful. Good luck with your scope choice.
Wonderful video, I would have paid for it! Very informative, concise and easy to understand. Thank you! I look forward to watching more of your videos!
You just saved me a lot of time and money. I’m sure I will eventually wind up with a refractor, but I’m going to choose the discipline of the SCT. THANKS AGAIN 👍
Great, Joseph! I started with the SCT. There are plenty of resources to help with issues you will encounter. Welcome to the learning curve.
Thank you for the education and sharing of your experience. Every tool has it's place.
Any excuse to buy a new telescope...I mean "tool". Thanks for watching, Jason!
Wonderful overview and well presented- thank you. 🙏🏼
Thanks, Ted! Been a while since I made that video and have added a William Optics GT81 (385 mm focal length) to the lineup and I still stand by my conclusions: the SCT is the most versatile year-around scope, but what a beating… Enjoy the night!
THANK YOU for that comparison. I’m about to make my first purchase and I was planning on a 115 APO f/7.0. Keeping portability in mind was a big factor for me and you helped me especially showing images to ensure I will have the equipment to get similar satisfaction. FOLLOWING!!!
You’re welcome! Glad it helped. Remember to consider the sensor size of your imaging camera as its size affects the apparent field of view. I image with the ZWO ASI1600. If your camera has a larger size, then you will see a larger field than my pictures. If your camera’s sensor is smaller, your image will be clipped. Good luck!
@@Aero19612 That was another thing I learned from your video that I haven’t heard before. Thanks
A very useful video. You explained a lot. I found it a very interesting video. Just wish we had more clear skies here in the UK. Thank you.
Thanks for watching, David! Yeah, you guys have a more difficult time than I do in finding good nights for imaging. Good luck with that!
Great assessment and observations! Cheers!
Awesome! Thanks for watching!
Awesome photography, James. Very impressive.
Thanks! Truth be told, I’ve got quite a bit of room for improvement. Thanks for watching!
great analysis. I'm currently using my RedCat51, and I love the ease of use as you noted. My SCT hates me...but I will win over it's love....or die trying :)
Perfect attitude! We astrophotographers must teach our SCTs to play nice with others. In the mean time, we have the Redcat!
This is great info. I LOVE my RedCat 51 and everything stated here is true. It's just a joy to use. I have a 152mm triplet, a 8" Newt and an Edge HD8 and they all have a purpose. The refractors are the easiest scopes to get up and running.
Yep. I always dread “Galaxy Season”. Means more quality time with the SCT. Oh well. If it were easy, everyone would be an astrophotographer!
I really needed this Thankyou!
Glad you found it useful, Andrew! Thanks for watching
Nice. I always enjoy your thorough analysis of the various topics you do videos on. I was surprised that your WO GT81 didn't get in there. I find mine to be a nice versatile focal length with the adjustable WO FF/FR.
Haha. I have a good excuse: I didn't have the GT81 when I made that video. Thanks for watching.
@@Aero19612 ha ha. Laugh's on me for not following the timelines better 😄
your videos are so good for who is confused what to go for thankyou
Great, Gunjan! Good luck making a choice!
Nice analysis, and I agree with your pick, though in the end, the range of scopes you have is ideal (and addresses travel needs). I particularly like the FOV of the Redcat, bringing greater context to well known objects sort of like revealing the forest around a tree. No mention of RASAs that overlap into the Refractor FOV, with larger aperture. One add'l point to SCT's versatility is the addition of Hyperstar, increasing FOV and larger aperture (at the cost of a medium refractor!).
Of course, the hyperstar! I have never used that option. But that would turn that slow light collector into a wide-angle light-eating monster. Yeah, my list is not exhaustive-just my experience with what I have in my hands. Gotta do that hyperstar thing though. Thanks for watching, Dave!
Thank you, James. Extremely helpful for me as I consider purchasing my first scope. Very difficult these days even finding a scope in stock. I hope that changes soon.
Yes. The supply chain is all kinds of messed up. Very frustrating. My new EQ6-R mount just arrived after months on back order. Don’t panic buy something just because it happens to be available when you really want a different product. Astrophotography is all about the long game. Thanks for watching!
@@Aero19612 ~ Hi James, quick question, did you have to prepay for the EQ6-R? Thank you.
@@scottmac2032 Sort of. Bought it from Agena Astroproducts. You have to provide the credit card info when you order, but your card isn't charged until it ships.
Just managed to find a redcat in stock, gets here tomorrow. I'm pumped!
Excellent, Chunter! I bet it came with a week of cloud cover too. You'll love it. Thanks for watching!
This is a great summary, thanks.
Thanks! I hope that the video helps.
@@Aero19612 A little better informed toward an impossible choice 😄
That fish head shot is incredible!
Thanks for watching!
Very informative. Thank you!
Thanks for watching!
Medium APO (90-120mm) with a 1x flattener and .8, .65x reducers is the best for most imho.
Low maintenance, not super heavy or large, no columnation to worry about. Can be used as a lens during the day so they’re very versital and great results.
Not cheap if you want some focal length but worth the investment.
beautiful images with the redcat
Thanks! The Redcat does a nice job. After living in SCT world for all those years, it’s nice to see the “big” picture.
Very informative!
Dang what truth is resolved in this study, 100% spot on...live it love it run with it... It is all of this... from the novice to the master, find your passion, and run!
Excellent, well put together video, thanks! You have my subscription! Personally If I had to choose just ONE Telescope, I would pick my 200/1000 Newtonian Reflector. It can do almost anything, imaging wise. It also has the best "$/mm of aperture ratio".
For reference I own 66/400 ED Refractor, 200/1000 Newt. reflector, 203/1624 Ritchey Cretien, and various other Achromatic refractors that I don't use anymore. I'm 17 months into Astrophotography and 9 years doing visual Astro. Liverpool, England. Bortle 7.
Simply amazing !
Thanks!
Great video! And just my 2c, I think it might be worth pointing out the sensor size of the camera you're using, as this also affects the apparent size of DSOs in the frame.
You're quite right, Quincy. I had some discussion on that but then noticed how long the video was and cut it out. I did mention the camera I'm using, but, of course, for someone just starting out, that info would go in one ear and out the other. Thanks for watching!
Thank Jame like the way you thinking clear sky!!!
Thanks for watching, Jean-Claude!
Very informative video, thank you
Thanks for watching, Simon!
Thank you for sharing. I had the opportunity to see a rocket launch in 2018. Memorable experience. I shared a pretty fun montage of the journey to my page.
oh my god, shut up please
Outstanding video! I’m about to tackle an C11 that I purchased used. I’m especially concerned about guiding since I have a small refractor and a 120mm camera for it. The imaging will be done with a Sony FF A7RIII. Great information and comparison.
The C11 is a beast! Congratulations! Consider getting a focal reducer for it once you've gotten familiar with it. Thanks for watching, Michael!
I have probably watched a hundred beginner astrophotography videos. This one is in the top 5.
Thanks for watching, Ron!
Looks like I fell into some good choices, my refractor is a 711mm and my reflector is a 1624mm... all good info, thanks.
Yep. Good choices. Wait. Are there bad choices? Thanks for watching!
I am looking for a second telescope and this was very helpful. Thanks.
Great, Gene! Let me know what you end up with. Thanks for watching!
@@Aero19612 My current thinking is to go with a 180mm Mak-Cass on an Orion Atlas II mount. I'm avoiding astrophotography until I learn more but I want the option in the future. This will give me great solar system views as well as galaxies.
I have two scopes right now, a Celestron Nexstar SLT130 (reflector), and a Nexstar SE8 (Schmidt Cass); no refractors.
I find the SCT to be my most versatile right now - two focal lengths/speeds (3 with Hyperstar).
A RASA would be interesting.
That said, I’ve been thinking a lot lately about getting a good refractor, and my interest has been leaning more toward the RedCat71. I like the idea of being able to rather quickly and easily move it between indoors and outdoors, as well as put in the car and go if I choose. Sometimes, there’s only a short window of opportunity to use it any given night, and this portability is sometimes the deciding factor in whether or not to set up for a shorter period of time.
Enjoyed the video! 👍 (I know it’s a couple of years old by now, but good points made!)
Ha! The video may be 2 years old, but it’s “new” to you! A welcome peace of mind comes over me when I switch back to a refractor. A Redcat 71 is a great choice. You’ll enjoy it for sure. Clear skies!
Subbed. Great video thanks
Thanks for watching! and subscribing!
I think the most versatile scope on the market that covers everything and can do all kinds of astrophotography is the Celestron SCT, the evolution series can either use an f6.3 reducer or hyperstar at f2. They are the most useful multi purpose scope on the planet. Good for planetary and the best scope for astrophotography as you can turn it into F2 and at those speeds aperture rules big time.
I agree, Dennis! I haven't even scratched the surface with my SCT by going to the Hyperstar system. One day, maybe. Clear skies!
Great video.
Thanks, Rick!
Super helpful! I bought a Celestron 6SE two years ago as telescope supplies then pretty sparse. Added the Hyperstar and nothing like imaging at f/2. 😊 That said, now that supplies are more available, trying to sort out what to get next. Moved to Arizona recently, so looking for what next to get some longer reach. BTW, got the AM5 mount, love that. Thanks again for the helpful video!
More options than there is money (in my wallet anyway). I’ve never imaged at F2, so can’t imaging the double-takes that’d cause. The AM5-like mounts are intriguing. I must say, not having a counterweight makes me nervous. Not sure if there’s a counterweight option for that mount. Thanks for watching!
Yes, you can add the counterweight if desired, zwo recommends them if payload > 26 lbs. Mount is very portable. F/2 is amazing, most of my subs are 30 secs or less. Thanks again for the video, you have me leaning towards the 8" edge hd.
@@nameisunique Haha. Enjoy the Bin-1, 30-sec exposures from the ASI294MM! Maybe get a sack of external 3TB SSD drives!
A wonderful video. I was gifted a lovely Celestron 5SE as my first (and currently only) scope. Unfortunately my main interest is photographing galaxies and I don't have the funds to get a decent EQ mount, so I'm stuck with the NexStar mount! Not that I'm complaining about being gifted a very nice scope - I like it a lot for visual use.
I have a Star Adventurer tracker and a good camera so I think I'll be getting used to the fundamentals on that first at much lower focal lengths whilst saving for a good mount. I have accepted that I'll have to put galaxies on the back burner in most cases (with the obvious exceptions) until I know what I'm doing!
Trust me to enjoy the idea of the most expensive option.
Thanks for watching, Duncan. I, like you, wanted to take images of galaxies. You'll get there. Learn what you can with what you have, and then take a step. All it takes is $$
@@Aero19612 Thank you James. Much appreciated.
Interesting as ever. One thing to add would be the use of Hyperstar on SCT’s by Celestron. Adds cost but gives widefield views and very fast optics. My 8inch Edge goes from 2000mm F10 to 425mm F1.9. However, you are correct in saying that SCTs present huge issues in so many ways so for beginners I’d say go for an 80mm or 102mm refractor that offers a good field flattener AND focal reducer as add ons if you want them.
Thanks, John! Yes, someone else mentioned the Hyperstar. That's definitely a hole in my astrophotography game. I looked up the Starizona system, so it's about moving the hole in my game to a hole in my wallet. Still, it makes sense. The small refractor advice for beginners is sound. I just think a beginner would benefit from seeing what scope selection does to your available target list.
James Lamb The entire imaging thing has cost me a fortune! My first scope was 200mm Newtonian which I still have but rarely use. At 1000mm focal length it was great for Lunar and things like M42 or M33. Its just so big to lug around. I think an SCT would have been a better choice but the Newt was so much cheaper. Think if I was starting it now I’d go for a Redcat or one of the 61mm scopes that have launched recently with a OSC like the asi533 and a dual band or Tri band filter. Portable, easy to setup, forgiving of guiding/seeing and not too expensive. Then I’d add an SCT later for lunar/planetary/galaxies etc.
In the end it all comes down to apperture and resolution and mount capacity with it. Pixel/scale is also something that comes into play. Then there is seing. 1000mm I would say is where I would use if I could chose
Hi Rafael. I agree with you. 1000 mm is a good mas focal length. If you haven't already, see my more recent video that discusses those issues:
czcams.com/video/H-cAbF25gcI/video.html
Thanks for watching!
Super informative video, thank you. Given the relative ease of use of the apochromatic refractors I am thinking they would be a good place for a beginner to start into astrophotography with a telescope, after an introductory beginning with a simple DSLR and tracking mount. At least, this is the approach I am thinking of taking. Then if early successes continue to suck me into this hobby, I would eventually want to get a longer focal length reflector for more challenging targets after I've first learned the basics. I don't see a lot of downside to this approach because, as you mentioned in your video, even as experienced and skilled as you are, you still enjoy using your Redcat for various things. I am looking at something along the lines of the Williams Optics Gran Turismo 81 IV, focal length 478, diameter 81mm, and f/5.9. Any thoughts on this approach? Thanks again for a great video.
Good approach. Good selection of a scope. I'm still trying to put my info together for a video review of the 4 or 5 targets I shot with the GT81. No complaints. Love the scope. Here's the things you should give some thought to: The DSLR is a great camera to start with. If you decide astrophotography is not that fun (or you don't have enough cuss words in your vocabulary), you have a DSLR you can still use. Bonus! BUT: that scope is best suited for wide angle targets like nebulae (most galaxies will be very small in your field of view). Many nebulae are "emission"-type which means you really need narrowband filters to capture the colors that are emitted (Hydrogen-alpha = red/orange, Sulfer-2 = red, and Oxygen-3 = teal). A DSLR captures in broad red, broad blue, and broad green so it won't see these colors very easily--your pictures will generally be red. There are single filters that have narrow passbands at those colors, but they're about $1000ish (I don't shoot one-shot-color images anymore, so research this issue a bit). If you do use one of those filters, you'll want to (need to?) expose for a long time, say, 5 min long. But a tracking mount is only good enough for a 30-sec exposure because star streaks will start to show up. You can take lots of 30-sec exposures, but they'll take up 32MB per image and about 64MB once you start the processing. You'll need lots of hard disk space, but that's easy now a days. Welcome to the slippery slope of astrophotography. All of that said, plenty of people take your approach and get great results. Then, as you say, you can decide which way you want to go. Good luck! It's a great hobby. I know many cuss words.
@@Aero19612 Thanks. I'm thinking DSLR for now because that's what I have on hand. It's my wife's camera, a little old, nothing fancy, but something to start with (Canon Eos Rebel something or other). With the price of something like the Canon EOS Ra (filters adjusted for AP) being around $2,500, I can't justify buying another DSLR at that price. Perhaps I would just go to a dedicated AP camera after fooling around with my old DSLR. Any beginner-oriented suggestions along those lines? Thanks again!
I would (and did) cut your teeth with your DSLR. I wanted to shoot galaxies when I got in so I got my C9.25 SCT and a Canon T3i. Worked great for an intro system. I got tired of using a non-cooled camera in Texas and that's what led me to a dedicated cooled DSO monochrome camera. For the $2,500, you can set yourself up pretty nice with a very versatile mono camera and filters. You've set yourself a good course there.
Nicely done
Thanks, Sean. And thanks for Watching!
Absolutely! You did a really great job with this. I'm mentoring a few people and your video saved me from a bunch of emails and texts. I just said "Go watch this. It explains all that I'm trying to get over to you!" Appreciate it!
Sean
Finally got the answer why I want telescope with big FL!
Haha. But it sure is less stressful to use a short focal length! Thanks for watching, and good luck with that long focal length scope!
Im happy with my edge 8hd. Have the hyperstar. Its not always easy, but int that hard either. Gives me the oppurtunity to use the scope at 3 focal length´s. Havent got the celestron reducer yet. But for imaging. I can dearly reccomend a motor focuser. I have the microtouch variant. It is of very good quality. Bought it before the Celestron came out. so I can not compare. But looks to be good value. Microtouch is superb quality though.
Agreed. When you consider the baseline scope, the f/6.3 focal reducer, and Hyperstar, it's really the multi-tool of telescopes. Thanks for the focuser comment. I may look into the Microtouch. Also, ZWO is coming out with an adapter for their focuser and SCTs. Thanks for watching!
James, the pictures are beautiful! I really liked the video and especially the summary was spot on!! I have a particular slant to Meade, as I have a 8 inch SCT which I love (but need to defork it to a GEM if I want Galaxy Photos) and now I want to get into DSO work more as my kids are off to college! Im in love with the Meade APO Quad, do you recommend any other APO's and suitable mount? Thanks Simon UK
Thanks, Simon! I've got my eye on the EQ6R Pro as my next mount (in my preferred price range). Meade makes good scopes, no doubt. And, I imagine the quad will give you a flat field. Can you get a focal length long enough for galaxy imaging in a quad?
@@Aero19612 Hi James, No I don't I of any, more the Quad ( I should be clearer) for Wide Field and the 8 inch SCT for galaxies. So, really any other APO's do you recommend other the MEADE ? :-) Thanks!
Oops! My bad. Well, I've been very happy with the two William Optics scopes and the one Explore Scientific scope I have. I would not go so far as to say they are "better" than the Meade. I doubt that is the case. If they are at the same price point, they are probably on par with each other. I will say that I'm very happy with the WO GT81iv + Flat6Aiii (field flattener and focal reducer) because:
1. The adjustable field flattener is easy to set so as to flatten the field-I'm still having issues getting a flat field with the non-adjustable field flattener I have for the Explore Scientific. You probably won't have to deal with this if you get a quad design.
2. The GT81 has a standard knob/rack and pinion focuser that pairs well with established auto-focusers on the market like the Pegasus Astro and ZWO EAF. My Redcat has a helical focuser and while there are focusers out there, I just don't trust them as much (belt drive vs direct mechanical connection).
3. I think the 385 mm I end up with is a good focal length for larger DSOs
You can't go wrong! Let me know what you finally end up with.
@@Aero19612 James thank you so much for taking the time to help me. I am looking at a few APO ED FLP 53 types ranging from Doublets & Triplets second hand which is about 50% of the new price listed so, I can learn more from the scopes and increase my "training" in the Astrophotography arts. I have the funds to buy a Meade 70 mm Quad and new EQ6 R but think I will not learn anything from this (other than my wife saying I told you so, which would hurt more) :-) so I think a second hand APO, EQ3 and a Mirrorless DLSR (Canon as I have a Nikon DX40) to get me off training. I will of course let you know. I have been taking star trails using Go Pros, my little ETX stacking Orion and moon pictures, Webcam on Mars, Jupiter and Saturn with my 8 inch SCT so very familiar with the hurt, pain and patience learnt so far :-) thanks again James for your time ! Regards Simon
I will be upgrading to the Redcat 51 with my ASI 294 after using my Tamron 150-600mm Telephoto. I do love the nebulae and most of my Nebulae images would indeed suit the Redcat 51.
Love the RedCat! Check out this video while you're at it if you're interested in autofocus options: czcams.com/video/EkChJxEiYiA/video.html
Thanks for watching, Paul!
I've got a similar bunch of options. But done on a far smaller budget.
Great video James. I notice your SCT isn't the HD version. Is that because you think the HD isn't worth the extra cost?
Thanks for watching, Mark! No, the SCT was my first telescope and its selection came down to two points:
1. A friend had the 8" version and I liked his pictures
2. I bought the SCT, the CGEM mount, a guide scope, a guide camera, and other gadgets all at once and wanted to keep costs "down".
I never even considered the HD, assuming it was out then (2014ish}. Your question is a good one and maybe even more complicated than just comparing optical quality of the two scopes. One should also consider seeing conditions where you will image from and the quality of the mount with respect to guiding (DEC backlash and RA gear noise). The best optical system can be brought to its knees by other contributors. Mind you, I have no magical means of balancing those issues so I'm of no help whatsoever. Compare the specs and the cost difference and if it sounds fair, go with the HD version if you're thinking of jumping in the SCT pool (assuming you're not in it already).
This is an extraordinarily helpful video. On the ED102 were you using a reducer/flattener?
Thanks for watching! Yes. At that time, I had the Explore Scientific field flattener (not reducer) but have since switched to the Hotech flattener (also not a reducer).
@@Aero19612 Thanks! I was shopping for a wide field scope and wondering if I should factor focal length reduction into the views you portrayed.
Given your suggestion that an APO refractor is well suited to a narrowband imaging system, do you think it's worthwhile to spend the extra on a triplet or just go with a doublet, since the main difference will be in the performance of the colour correction which has little to no impact on narrowband imaging? Nice vids, keep them coming!
VERY good and interesting question! Answer: I don't know. I agree that narrowband will show less color separation because Ha and S2 are in the red and O3 is kind of middle of the road in the blue/green. Plus, the nature of the target (gaseous nebula) is more forgiving to color separation I suspect. I certainly don't have expertise/experience to give you a definitive answer, but you have a very good point that could save you big $$. Thanks for watching, Steve!
I like your thinking here. I have the WO ZS126 and have minimal chromatic aberration even with OSC on all but the very brightest of objects like moon and planets.
With regards to the Heart and Soul nebulae, the Redcat 51 is perfect for the pair with most cameras. I have an APS-C camera a I hope to try the pair with my Sharpstar 61EDPH ii.
Yep. A larger sensor camera (I'm using the ASI1600) would likely give you a nice view of both. Your APS-C might just do the trick. With your focal reducer, you'll get about 270 mm. May take some careful framing. Thanks for watching and good luck!
You can also use Celestron SCT's with a Hyperstar adapter to give you the wide field of view you enjoyed for "nebula hunting" while benefitting from an even greater aperture. A modified SCT with its native FL (plus Barlows for planetary work), reduced FL and Hyperstar FL will do anything you need provided you have the cameras to go with it. The only thing these telescopes are terrible at is travel to far off destinations by commercial airline. But even that is doable with the right case and a great deal of faith in baggage handlers. Otherwise, go with a carry on option.
The SCTs are remarkably versatile, especially when you consider the Hyperstar system - of course, that costs as much as a telescope in its own right. I must say, I do enjoy the portability, image quality, and reliability of the refractors though. Thanks for watching!
My first thoughts were of the RASA as well. Great video, I debate back and forth all the time on my next scope. I started photography with an Edge HD 9.25 and it has been a bit rough, particularly since I started with an OAG as well at that high focal length. With the explosion of the popularity of astrophotography over the last few years, I am curious to see the innovations that will come from industry to fill the void. I think I am going to go all in and get a Tak Refractor as my next step, but I'll never stop using the SCT for pictures as well.
Thanks for watching, Roger! The Taks are amazing scopes. I don't think I could swallow the cost though. With my luck, the perfection of the scope would reveal all of the imperfections in my other equipment and I would have to start buying all new stuff. Good luck!
I really like the mid lengths, I have a 300mm ish scope but my 650mm refractor does most the work. I would love a slightly slower RASA, like a F/3
Agreed. That focal length is a good balance between convenience (carrying it around) and target selection. Thanks for watching!
There are some f/3 RASA-like reflectors (Riccardi-Honders), but the prices are rather... astronomical :)
Very helpful. I'm interested to know what's the tripod and counterweight system you have setup? Any information would be useful. Thank you.
I just have the standard Celestron tripod that comes with the CGEM mount. I have 1x11-lb counterweight and 1x17-lb counterweight. I need both counterweights to balance the C9.25, just the 17-lb weight for the ED102 and the Redcat. Thanks for watching, Bruce!
The 40" Yerkes telescope is an achromatic doublet with a 24,800mm focal length @ f24.8. So, refractors can achieve a high focal length.
Haha. I was commenting on the availability of affordable long focal length refractors for the backyard astronomer. There's a reason why reflectors take over at the long focal lengths
Great video. Imaging at 2200mm is no mean feat... Have you had any experience using focal reducers with the SCT?
Yes. I have the 0.63 focal reducer/corrector for the SCT that knocks the focal length down to 1400 mm, which is really good for M101, Leo Triplet, and the M81/M82 pair. I don’t use it as much as I should. Thanks for watching!
Must have missed it somewhere, but didn't see reference to the sensor size in combination with the focal length relative to the field size. Beautiful images. Maybe could notate the images at the video end with fl data, but still Beautiful.
You're correct. I mentioned the camera I used when I first showed the images from the Redcat 51. I had planned to include discussion of the role that the sensor size has on the images but after I recorded the image presentation part, the video was 30 min long, so I went on a slash and burn editing rampage to cut the length down. Yeah, and I thought about adding the focal length to the final image montage, but I took the lazy path instead since the focal length is presented earlier with the picture of the scope. Thanks for watching, Daniel!
Ah yes the asi1600 - 4/3" 17.7 X 13.4mm this is still a great presentation as many beginning astrophotographers (i include myself here) don't grasp the overall framing and choosing the right focal lenth in combination with sensor size to create the best presentation of their chosen subject. And then throw in the change of scale when adding a reducer flattener into the optical train. There is a number of great preplanning software programs out now to plug in your scope/camera/reducer info then use the created frame tool to see how objects fit the frame and camera rotation.
Your presentation is great. Really shows framing perspective. Thank you for taking the time to present this video, I know it is a lot of work.
Thank you for the video
IMHO I think that the most important parameter is the average local seeing. I've choosen my photo setup with this only criterion.
In a nutshell : average local seeing vs image scale.
It has often been my experience that resolution is better with 749 mm focal length ( Askar 107PHQ + IMX 571 ) than >1000 mm focal length SCTs or RC or newts.
Central obstruction cannot been overlooked.
Yes, seeing is a BIG factor. I think the ~1000 mm is a good target. Thanks for watching!
I just started astronomy with a 10" Dobsonian.
I'm hooked.
Already researching which used DSLR to attach for planet and lunar images.
I wouldn't mind a couple of recommendations if anybody wants to chine in.
Welcome to the hobby. I started out with a Cannon 550D (T2i). I used Backyard EoS to control the camera. But there's a Nikon version now too. It used to be that people would recommend Cannons because of the live view functionality but I'm not sure if other manufacturers have included that as well. Good luck, Rick!
Hey! Love your videos!
I’m looking at getting an actual telescope moving up from a canon 70-200 2.8 camera lens. Is it worth going for something bigger than a redcat 51/61 to get a different FOV than I’m use to? Or will I still be blown away at the difference vs the regular lens?
I just have a star adventurer 2i so weight is quite important
If you stick with that mount, you’ll want to stay on the shorter end of the focal length scale that is more tolerant of guiding/tracking errors. I’d suggest an upper limit on aperture of about 80mm (
@@Aero19612 thanks for the reply! Really appreciate it!
I’ve been able to get decent 60-90s subs at 200mm with my current setup in a bortle 6 city backyard. I feel like I do a really good job of polar aligning and balancing lol
Next clear night I’m going to try with my 70mm and see if I can do even longer subs while keeping good star shape (…realizing now you said 80mn aperture lol sorry still learning coming from 15+ years as a photographer)
Am new to hobby. I have a Celestron Omni 150mm XLT Newtonian reflector and CG-4 mount. Orion Observer 134mm Newtonian reflector and a Sky Watcher AZ GTi mount with a Bresser 102/460 doublet refractor.
Am thinking of starting astrophotography. Trying to decide if I should buy a Celestron 8SE or an Orion 8" Astrograph Newtonian reflector. Thanks for your informative video.
Welcome to the hobby. Challenging, but rewarding. Oh, and expensive. Clear Skies!
@@Aero19612 I now own 11 optical tubes. I have found, thus far, that my most versatile kit I have is my Celestron 6" Schmidt Cassegrain with a 0.63 reducer/corrector and a Hyperstar 6 v4 on a Sky-Watcher Star Adventurer GTi.
1) Inexpensive. Total cost with asi294 camera is only $2700.
2) More difficult than a refractor and less than a Newtonian. Entire rig with a asi2400 camera is only 16 pounds plus counter weights.
3) Can shoot at 1500mm (f/10), 945mm (f/6.3) and 300mm (f/2).
Just subscribed.
As much as I distrust Celestron mounts their lineup of scopes is generally not bad once you get away from the entry level. I can see a hole in your lineup that the RASA would fill nicely. Hard to argue against f2 with a mid range FL. PITA for narrow band and filters are expensive @ f2, perhaps it's better suited to OSC if all in one night is your thing.
Timely comment, Rob. My CGEM has an issue with an encoder (happened once before). The motors work, but it doesn't move to the right place. So I may be down for a while. I must say, I do think the C9.25 does a decent job. I wonder how much better the Edge HD series is? People talk about the RASA, but I've never seriously looked into it. Maybe I'm afraid I'll buy one if I do.
@@Aero19612 Bummer, sorry if I put the hex on it :) Don't throw good money after bad is my advise. I assume they are still pushing the Mission Impossible (the TV series) line with the focuser adapter ring
Agree about good money after bad. As it turned out, I had to drive down to the Texas coast for work this week and passed through Houston where there is one of the few remaining brick and mortar telescope shops (Land Sea & Sky). They don't make a point of mount repair, but I left the mount with them anyway. They tightened some loose screws, re-meshed the gears, and cleaned the electrical connectors. I picked up the mount on my way back through. Not sure if anything is fixed or not but will test it in a few days when the weather clears. Next time, I will open up the mount and check things out myself. Want to avoid Celestron Service at all costs.
Also there is huge amount of coma on
I mean you can always use a reducer
12:12: According to your chart it looks like there is a 1500 mm Celestron SCT that works for AP for 400 dollars. Which model would that be? Thank you.
Must be the C6 for $600
TL;DR: 18:00 but it's a really informative video.
if you want to see go with long focus telescopes!, if all you want are pictures then the shorter focal lengths are for you!.
Just a comment regarding refractor cost: the price does not go up by focal length, in fact long focal length refractors do not require the best glass. The cost of refractors is driven by aperture, and then increases further by SHORTER focal length; i.e. a f4 is much harder to make than an f10
Hey Tim. Perhaps a distinction without a difference. I did mention that the glass is the cost driver. Telescope manufacturers, as you say, aim for f/4.5 to f/7. As a result, you get the cost vs focal length chart I show in the video. So, in any real sense as a telescope buyer, you will find cost increases with focal length whatever the underlying trade offs are.
Lower focal length is generally the easiest to use in the most versatile
I’m on the market for a bigger focal length and I have a Rasa 8” it’s fast but short and because of its size a strong breeze destroyed my night, than I’m jumping on a refractor with around 950mm in FL, any suggestions?
Hey Cleston. I don't have experience with a refractor at that focal length. I have a very good opinion of Explore Scientific and William Optics scopes. Of course, Takahashi is top of of line, but VERY expensive. Take a close look at the weight of the scope compared to what your mount can handle too. Carbon fiber tubes cut way down on the weight, but at a cost (of course). Good luck!
Interesting video, how bad is the light pollution there ? Do you live in a city, small town or village?
I live north of Dallas. The LP is between Bortle 7 and 8
Which is best option refractor or reflecter telescope..?
Tough question. If your seeing is typically on the bad side or if you have lighter mount (e.g., Celestron AVX or Sky Watcher HEQ5), go with a refractor with focal length of 700 mm or less. If you want to image a lot of galaxies (except for the "big" ones: M 31, M 33, M 101), then you'll need some real focal length and the SCTs (reflectors) become mor cost effective. But you'll need a pretty good mount and good seeing. My EQ6-R is barely good enough. The EQ8 is much better. Hope that helps some!
Hi James, great vid! Here’s a question for you… newbie wanting a telescope, wants beautiful visual experience, ease of use, and options for photography. I can spend upwards of 6-7k… do I choose 120mm refractor or 8” SCT? Any advice greatly appreciated!
I’ve just watched your vid again… I know you explain everything very well, but I still feel unsure with the decision!! 🤔 Can a 120mm APO be the “do all scope”?
I’ll throw in a couple of comments. An 8” EdgeHD will run you about $1400 for 2000mm focal length. Good for galaxies, small nebulae, and planets. With $200ish focal reducer you’ll have 1200mm focal length. Good for galaxy groups (Leo Triplet and M81/M82 pair). Most triplet refractors at 120mm to 127mm aperture will cost twice that. You’ll need at least $1800 for a mount if you don’t have one. Another $2000 for a cooled Astro camera (lots of options there). I do like my refractors and like the autofocusers you can get for refractors.
Think of what targets you’re interested in and use the oculars option in Stellarium to see what field of view you get with the refractor vs SCT for the camera sensor you have and see if the object is too big or too small. You really can’t go wrong and will eventually end up getting other scopes. You’ll enjoy whatever you get. I doubt I helped at all!
@@Aero19612 ok thanks for that! But if we were to consider no photography, just visual enjoyment… which one? 😀🤔
I guess I would want max magnification and I would go with the SCT.
@@Aero19612 one more thought… does a “2x” doubler on a shorter focal length refractor not accomplish the same thing as a “reducer” on a longer focal length reflector?
Which field flattener do you have for the ED102? Explore Scientific or a 3rd party one? Thanks!
Ha. Both. I started with the Explore Scientific but didn't like the results I was getting so I switched to the Hotech:
czcams.com/video/Ror5OXKV8Sg/video.html
@@Aero19612 thanks for sharing. And also thank you so much for all the good info in your videos, because ES website is somewhat confusing to me.
I am looking to get the ED102 (moving up from 61EDPHII) and i thought there is a FPL53 version of it, but apparently this Hoya FCD-100 is their proprietary glass which is very similar in characteristics as OHARA’s FPL-53, at least that's what it says on the ES website. There's the FCD-1 with EMD coating, which comes with the aluminum tube and they call it the Essential version, then there is the FCD-100 with alu tube, and then there is the carbon fibre tube with the same FCD-100 glass (if i understand it correctly).
It is a nice focal length scope, and i hear a lot of good comments from other owners, so that's why i got interested.
Cheers!
I guess my explorer scientific 127mm f/7.5 with their 0.7x reducer/flattener would make a nice combination at 666mm focal length. Without focal reducer I have 952mm.
The 127mm focal length is a good scope. Without the reducer, you can get good pics of small galaxies and not have to worry about the non-flat field in the corners. For galaxy clusters and some nebulae, you can use the focal reducer/corrector and get good star shapes out to the corners.
Amen
Haha. But what a pain.